<div style="margin-top: 5vh;" class="layui-card"><div id="page-canvas" style="height: 80vh; border: 1px solid"></div><button v-on:click="changeBtn()" style="right: 10vw; position: absolute; top: 15vh; width: 90px;" class="layui-btn layui-btn-fluid">切换 </button></div>